@wizzwizz4 always great to see people thinking about identity! The project has been quiet lately but I am very close to releasing a better way of working with Keyoxide, not needing PGP, just pure Ed25519!
And after that, I'd like to experiment with methods based solely on domain ownership, no cryptography.
I don't fully grok OP's envisioned approach yet, but I suppose that's coming somewhat near?